Blowers (sometimes referred to simply as fans) in the power range of about 1 horsepower to up to about 10 or 15 horsepower are used extensively in industry for general ventilation and in fire fighting. Most such blowers are driven by electric motors or gasoline engines. The applicant invented and patented a water driven blower (Kapich, U.S. Pat. No. 5,121,124 issued Jun. 9, 1992), designed to be driven by the water in fire hoses, which has been extremely successful commercially and the United States Navy is currently in the process of purchasing one of these blowers for every ship locker for every major ship in the United States Navy. It is also known that blowers in this power range can be driven effectively by high pressure air. The applicant has invented a quiet air driven fan (Ser. No. 07/750,272) with axial fan blades and air turbine blades mounted on the hub of the fan blade.
Blowers are often purchased for emergency use, for example, fighting fire or smoke or fume control or personnel ventilation. It is not unusual in such situations to lose electric power source or to lose a compressed air source. Often both such sources are lost but in many cases one of either compressed air or electricity will be available.